Conventionally, there is a system wherein information (contents) such as music is encrypted and sent to an information processing apparatus of a user having executed a predetermined agreement so that the user may decrypt and utilize the contents on the information processing apparatus.
For instance, as shown in FIG. 116, a case where two contents sending apparatuses and one contents receiving apparatus are provided will be described.
First contents sending apparatus 600 comprises data encryption section 601, data encryption section 602, content key generation section 603 and tamper resistant memory 604. Moreover, the tamper resistant memory referred to here may be any such memory as will not have its data easily read by a third party, and no hardware-wise limitation is required in particular (for instance, it may be a hard disk placed in an entry-controlled room or a hard disk of a password-controlled personal computer). Tamper resistant memory 604 stores distribution key Kd necessary to encrypt content key Kco supplied in advance from an electronic distribution service center (not illustrated).
In order to generate data to be delivered to contents receiving apparatus 620, first contents sending apparatus 600 generates content key Kco1 by using content key generation section 603, and encrypts contents by using this key at data encryption section 601. Also, content key Kco1 is encrypted by using distribution key Kd at data encryption section 602. These encrypted contents and content key Kco1 are sent to contents receiving apparatus 620.
Incidentally, like contents sending apparatus 600, second contents sending apparatus 610 comprises data encryption section 611, data encryption section 612, content key generation section 613 and tamper resistant memory 614, and generates content key Kco2 at content key generation section 613, and encrypts contents by using this key at data encryption section 611. Also, data encryption section 612 encrypts content key Kco2 by using distribution key Kd supplied from the electronic distribution service center (not illustrated). Thus, second contents sending apparatus 610 sends the encrypted contents and encrypted content key Kco2 to contents receiving apparatus 620.
Contents receiving apparatus 620 comprises sending and receiving section 621, upper controller 622, encryption processing section 623, memory 624, data decryption section 625, data decryption section 626 and tamper resistant memory 627. Moreover, as there are such an indefinite number of contents users that it cannot be grasped how they will handle the apparatuses, the tamper resistant memory referred to here requires its internal data to be protected hardware-wise, and thus encryption processing section 623 is a semiconductor chip of a structure difficult to access from outside and has a multilayered structure wherein the tamper resistant memory inside it has characteristics making it difficult to illicitly read data from outside such as being sandwiched between dummy layers like aluminum layers and having a narrow range of operating voltage or frequency. And tamper resistant memory 627 stores distribution key Kd supplied in advance from the electronic distribution service center (not illustrated).
Incidentally, while tamper resistant memories 604, 614 of first and second contents sending apparatuses 600 and 610 are the memories accessible from outside, methods of accessing them are limited. It may be password or entry control. On the other hand, as for tamper resistant memory 627 of contents receiving apparatus 620, the memory itself has a structure not to be illicitly accessed from outside, and there is limited or no method of reading its internal data from outside by formal means for access. Moreover, while it is impossible to read internal data of tamper resistant memory 627 from outside, there may be a method of access only capable of changing data from outside if former key data or the like is used. Also, in encryption processing section 623, it is possible to access a memory and read predetermined data, but it is impossible to read internal memory from outside.
Contents and content keys Kco1 and Kco2 sent from first or second contents sender 600 or 610 are received by sending and receiving section 621 and delivered to upper controller 622. Upper controller 622 stores such data in memory 624 once, and in the case of utilizing the contents, it delivers content key Kco and the contents to encryption processing section 623. On receiving them, encryption processing section 623 decrypts them by using distribution key Kd stored in tamper resistant memory 627 in advance in data decryption section 625, and then decrypts them by using content key Kco in data decryption section 626, and utilizes the contents. At this time, there are cases where it involves accounting.
Incidentally, in an information processing system shown in FIG. 116, there was a problem that a method had yet to be established for preventing the contents from being illicitly utilized such as providing illegal contents to the system or illicitly benefiting a third party due to accounting involved in use of contents.
Also, in such an information provision system, there are cases where recording and reproducing apparatus 630 shown in FIG. 117 is provided, and such recording and reproducing apparatus 630 has, for instance, record medium 640 consisting of MD (Mini Disk: a trademark) provided in a removable manner.
In this case, recording and reproducing apparatus 630 comprises sending and receiving section 631, control section 632, encryption processing section 633, expansion section 634 and external memory control section 635, and it stores distribution key Kd for decrypting content key Kco supplied in advance from an electronic distribution service center (not illustrated) to encryption processing section 633 and also holds save key Ksave unique to encryption processing section 633.
And recording and reproducing apparatus 630 has encrypted contents and content key Kco sent from first or second contents sending apparatus 600 or 610 received by sending and receiving section 631, and sends out the received encrypted contents and content key Kco to control section 632. Control section 632 holds the encrypted contents in record medium 640 via external memory control section 635, and sends out encrypted content key Kco to encryption processing section 633.
Thus, encryption processing section 633 decrypts encrypted content key Kco by using distribution key Kd, and then decrypts content key Kco by using save key Ksave and sends out content key Kco encrypted by the save key Ksave to control section 632. Thus, control section 632 has content key Kco encrypted by save key Ksave held by record medium 640 via external memory control section 635.
Moreover, in the case of utilizing contents, in recording and reproducing apparatus 630, control section 322 reads encrypted contents and content key Kco from record medium 640 so as to send out the encrypted contents to expansion section 634 and also send out encrypted content key Kco to encryption processing section 633. Thus, encryption processing section 633 decrypts encrypted content key Kco by the save key Ksave and sends out acquired content key Kco to expansion section 634. Thus, expansion section 634 decrypts encrypted contents by using content key Kco and is accordingly capable of using the contents.
In such recording and reproducing apparatus 630, however, even if record medium 640 is loaded, for instance, on a recording and reproducing apparatus other than recording and reproducing apparatus other than recording and reproducing apparatus 630 used for recording contents by holding content key Kco encrypted by save key Ksave unique to encryption processing section 633 on record medium 640 and having the save key Ksave held by encryption processing section 633, the contents recorded on record medium 640 cannot be reproduced on the other recording and reproducing apparatus since it does not hold the save key Ksave used for recording the content key Kco.
Therefore, such record medium 640 had a problem that its versatility is remarkably low in spite of being provided in a removable manner to recording and reproducing apparatus 630.
In addition to this, recording and reproducing apparatus 630 had a problem that, even if a user wanted to utilize the contents recorded on the record medium by recording them on another apparatus or another record medium, they could not be easily utilized since the record medium was provided in a removable manner.
Furthermore, the information processing system had a problem that, even in contents receiving apparatus 620, a method had yet to be established for preventing received contents from being illicitly utilized.
Moreover, contents receiving apparatus 620 to be connected to first and second contents sending apparatuses 600 and 610 had a problem that, as it is assumed to be owned by a user, contents cannot be easily provided for anyone else not in possession of the contents receiving apparatus 620.
In addition, the information processing system had a problem that, in the case where a user uses contents receiving apparatus 620 to record a plurality of favorite contents on a predetermined record medium and creates an album, the favorite contents had to be read and recorded one by one in the record medium by using contents receiving apparatus 620, which recording work was complicated.
Furthermore, the information provision system had a problem that, in the case where any contents of which transmission was stopped due to occurrence of a defect (occurrence of an error in data), for instance, was sent by mistake from first and second contents sending apparatuses 600 and 610 to contents receiving apparatus 620, it was difficult to prevent utilization of the contents on the contents receiving apparatus 620.